HTTP requests to the REST API are protected with HTTP Basic authentication. To learn more about how Twilio handles authentication, please refer to our security documentation. In short, you will use your Twilio account SID as the username and your auth token as the password for HTTP Basic authentication.

Twilio's Voice API is a flexible building block that can take you from making your first phone call.

While we hope this page gives a good overview of what you can do with the API, we're only scratching the surface: check out our troubleshooting tips to learn about Twilio's debugging tools, common issues, and other tools and add-ons like Voice Insights.